Voltage control circuits



Oct. 10, 1950 P. w. REDCAY VOLTAGE con'mor. cmcvns Filed Dec. 20, 1944 WX M /Nl/EN 7-01? 50 c4 1 Arrae/V Patented Oct. 10, 1950 I VOLTAGECONTROL CIRCUITS Paul W. Redcay, Washington, D. 0., assignor totheUnited States of America as represented by the Secretary of WarApplication December 20, 1944, Serial No. 569,073

4 Claims. (Cl. 179171) (Granted under the act of March 3, 1883, asamended April 30, 1928; 3'70 0. G. 757) The invention described hereinmay be manufactured and used by or for the Government for governmentalpurposes, without the payment of any royalty thereon.

This invention relates to means and methods for supplying current to thefilament of an elecn the operailien 0 the device the alternattronic tubewithout usinga'filament battery. ins vol -a e supplied by an audi oscillor at A primary object is to supply current, at subsome definite frequ yi Eh-IOUgh agency stantially constant R. M. s. alternating voltage, famplifier tube l2 a d transformer 22, fed to forelectronic tubes used inradioor other milifilament other load resistor The filament tarydevices. This voltage is. derived from a Voltage appearing acrossSecondary 25 of Small wind driven generator m; m fietransformer 22 isadjusted in value by means of vice to furnish plate or B voltage as wellas fila- Potentiometers I4 and The rectlfiers and m t current V 26, onconjunction with the associated elements, A further object is to providea circuit for au- 15 constitute a d0u b1mg Circuit to providetomatically regulating the fil m t Voltage by the necessary negativebias automatzcallyto admeans of simple changes in or additig s to existJust the output voltage. Condenser I 21 is used ing circuits. as nAnother object is to provide a filament voltage Wlth Swltchfi and 24 mOff POSIHPH: regulation circuit to prevent filament burn-outs Open adirect u n voltagnalpphed i in case of improper load, to prevent meterover- Fween l f ii 2 7 2 3: f g loads 1f the filaments of a test modelare accl- .?ISi' g ai po 9 3 z dentally dlsconnected, and toautomatically eom- J O 1 f V0 f 2 7 pensate fortvariable loads 0n thesecondary of a '25 :iffgggf z gfg izi gfi g155 232 313 2 connectedransformer. Other objects will appear in the specification. i gig ggg gfig gfi i g ggfg "3 2 f g ii i f ifig ggifg gi iggg 3 33 at the groundend of the resistance. The confilament supply invention. Electricalpulsations tr arm of pitejntiometer.zs then adjusted an to the controlgrid H of tetrode. through (mnbias voltage at point X should then be thesame denser and part of potentlomete'l reslstance as before switches isand 24 were closed with reconnected between condenser l3 and thenegaspect to ground The reason for this is that the t1ve.termma1 ofrectlfier Wmch prefemply alternating voltage component appearing at thecns.1sts of a Stack of 8816mm or 6.010 per i anode of tube I2 is passedto the rectifier buttons recnfier buttons The negatlve termma-l of sumthrough condenser Ill and, as a result of the recllafr rectlfier 15connected to the posmve tifying action of rectifier 26, the positivehalf muilal of rectlfier W by means of conductor t cycle charges thiscondenser to full peak value. Whlch the negatlve terminal of condenserBecause of the way in which rectifiers 26 and i5 s Ponnected throughSWItCh The pQsltlve areconnected, this charge is held during thenegtermmal of condenser H is connected to the plate ative half of thecycle by the condenser plate I9 of tube 12. The primary 28 oftransformer connected to conductor m Thus during the 22 is connectedbetween Plate and the p051 negativehali of the anode voltage cycle theside tive5termina1 of the 3 supply which may be a 5 of condenser llconnected to lead 16 is forced to generator. Potentiometer 23, connectedbteween go more negative since t nduring the the ground of tube and theterminal, has negative'half of the cycle is superimposed on the sw tch24 con e ted as sh w h p u voltagedue to the held charge. The resultingometer slide contact 25 is connected with the voltage, therefore, whichis developed at lead i6 Po i in of ec ifi The grid- 5 is substantiallytwice the amplitude value of the ground circuit includes condenser Zl inser s, alternating current component of the anode voltand resistance 28and by-pass condenser 29. age. This negative voltage is passed on byrec- Screen grid 36 is connected to the positive plate tifier [5 to gridll of tube l2. To bring about voltage supply terminal B+ which is alsoconbias conditions which exist after the initial adnected to groundthrough resistance 23. lustment of the circuit, that is, when switches18' The secondary 2! of transformer 22 is connected in series withfilament load resistor 35 and switch 32. Switches [8 and 25' are tiedtogether and are therefore thrown simultaneously to off-on positions.

and 24 are open, it is necessary to introduce a positive voltage intothe grid return circuit to balance out the negative voltage which hasbeen developed as a result of the insertion of rectifiers i5 and 26.This is accomplished by moving arm 25 of potentiometer 23 to the rightuntil the voltmeter reads the prescribed value. With this adjustmentmade, the bias potential on grid II will be the same as that after theinitial adjustment of the circuit. The circuit is now adjusted foroperation as a regulated filament supply.

It will be noted that the polarities of the rectifiers l5 and 26 are soaligned that current passes through them in one direction but not in theopposite direction.

The regulation of the filament'voltage takes place in the followingmanner. Suppose that filament load 3! is reduced so.that increasedcurrent fiows in the circuit to cause a smaller net voltage to beapplied to the filament. In that case the flow of increased secondarycurrent causes a reduction of impedance in the primary 20 of transformer22 so that the impedance drop in the primary will be reduced. Thisresults in a rise of potential at anode i9 so that an increased negativepotential will be developed on conductOr 16. Since this-negative voltagenow exceeds the positive voltage due to the setting of arm 25 ofpotentiometer 23, an increased negative voltage will result at point Xand will be applied through rectifier i5 to grid H to reduce the currentthrough the primary 20 of transformer 22 so that a reduced votlage willbe induced in the secondary or filament circuit. In like manner creasedif the filament load resistance is increased.

It will be apparent that while a direct current potential was assumed tobe applied to the 13+ terminal, the circuit will function eifec tivelywith an alternating current supply. In such instance tube [2 will alsoact as a half-wave rectifier. However, the regulating action describedabove will take place to keep the load supplied with power at thedesired voltage.

This voltage regulation system is particularly which a number of tubesare connected in parallel and some of the filaments are accidentally onopen circuit. It is of value also in compensating for lack of uniformityin filament resistance for various tubes and in preventing meteroverloads.

I claim:

1. A voltage supply and regulation circuit comprising a transformerhaving a primary and secondary portion, a vacuum tube having at leastthree electrodes, one side of said transformer primary connected to theanode of said vacuum tube, means connecting the remaining side of saidtransformer primary through a resistance to ground, a first rectifierconnected to a variable tap on said resistance, a second rectifier inseries with said first rectifier, means connecting the midpoint linkingsaid two rectifiers to said anode through a condenser and means to feeda fluctuating voltage to the grid of said vacuum tube through acondenser and variable resistance, the end of said variable resistancebeing connected to said second rectifier.

but in a reverse sense, the filament voltage is indesirable forcompensating for a condition in 2. A voltage supply and regulationcircuit coinprising a vacuum tube including cathode, grid and anodeelectrodes, means to feed a fluctuating voltage to the grid, a loadcoupled in the anode circuit of said tube, a source of direct currentpotential connected to the anode through the load coupling, and meansconnected to the load coupling for changing the grid bias of said tubein response to changes in anode current, said last-mentioned meansincluding rectifier means connected to the grid and responsive to theanode current to supply a negative direct current potential to the grid,and also including a variable resistor connected to the aforementionedsource of potential and to said rectifier means for introducing apositive direct current potential component in the grid circuit.

3. A voltage supply and regulation circuit comprising a vacuum tubeincluding cathode, grid and anode electrodes, means to feed afluctuating voltage to the grid, a load coupled in the anode circuit ofsaid tube, a source of electric potential connected to the anode throughthe load coupling, and means connected to the load coupling for changingthe grid bias of said tube in response to changes in the anode current,said lastmentioned means including a pair of rectifiers connected inseries to the grid, a condenser joining the anode and the leadconnecting the rectifiers, said condenser and rectifiers forming avoltage doubler responsive to the anode current to supply a negativedirect current potential to the grid, and also including biasing meansconnected to the aforementioned source of potential and to saidrectifiers for introducing a second component of electric potential inthe grid circuit.

4. A voltage supply and regulation circuit comprising a vacuum tubeincluding cathode, grid and anode electrodes, means to feed afluctuating voltage to the grid, a load coupled in the anode circuit ofsaid tube, a source of direct current potential connected to the anodethrough the load coupling, and means connected to the load coupling forchanging the grid bias of said tube in response to changes in the anodecurrent, said last-mentioned means including a pair of metallic oxiderectifiers connected in series to the grid,

' a condenser joining the anode and the lead connecting said rectifiers,said condenser and rectifiers forming a voltage doubler responsive tothe anode current to supply a negative direct current potential to thegrid, and also including a variable resistor connected to theaforementioned source of potential and to said rectifiers forintroducing a second component of direct current potential in the gridcircuit.

PAUL W. REDCAY.

REFEREN CES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

